Which statement is true about inner and outer hair cells?

Which statement is true about inner and outer hair cells?

• A. Outer hair cells amplify motion.
• B. They do not contribute to hearing.
• C. They do not transduce signals.
• D. Inner hair cells are the primary sensory receptors; outer hair cells amplify motion.

Answer: (D)

The main idea is that inner hair cells do the primary neural transduction, while outer hair cells boost the mechanical signal. When sound moves through the cochlea, the basilar membrane’s motion deflects the hair bundles. Inner hair cells are the main receptors that convert that mechanical deflection into receptor potentials and then release neurotransmitter onto auditory nerve fibers, providing the fundamental neural code for hearing. Outer hair cells don't primarily hand off signals to the brain; instead, they perform electromotility—changing length in response to receptor potentials—which amplifies basilar membrane motion. This cochlear amplification enhances sensitivity to quiet sounds and sharpens frequency tuning. So, the statement that inner hair cells are the primary sensory receptors and outer hair cells amplify motion captures both key roles. The other options are incomplete or misleading because they either ignore the transduction role of inner hair cells, overstate the ignorance of outer hair cells’ contribution, or misstate outer hair cells’ function.

The main idea is that inner hair cells do the primary neural transduction, while outer hair cells boost the mechanical signal. When sound moves through the cochlea, the basilar membrane’s motion deflects the hair bundles. Inner hair cells are the main receptors that convert that mechanical deflection into receptor potentials and then release neurotransmitter onto auditory nerve fibers, providing the fundamental neural code for hearing. Outer hair cells don't primarily hand off signals to the brain; instead, they perform electromotility—changing length in response to receptor potentials—which amplifies basilar membrane motion. This cochlear amplification enhances sensitivity to quiet sounds and sharpens frequency tuning. So, the statement that inner hair cells are the primary sensory receptors and outer hair cells amplify motion captures both key roles. The other options are incomplete or misleading because they either ignore the transduction role of inner hair cells, overstate the ignorance of outer hair cells’ contribution, or misstate outer hair cells’ function.